Soaking pit



y 2, 1929.- H. c. RYDING 1,719,453

SOAKING PIT Filed April 16, 1926 3 Sheets-Sheet 1 avwentoz flbtm k. W \W-N July 2, 1929. c; RYD|NG 1.719.453

SOAKING PIT Filed April 16, 1926 3 Sheets-Sheet 2 Mani Quota m1,

H. C. RYDING SOAKING PIT July 2, 1929.

Filed April 16, 1926 I5 Sheets-Sheet 3 Patented July 2, 1929.

UNITED STATES PATENT OFFICE.

HERBERT C. RYDIN G, O! BIBMINLGHAM, ALABAMA.

soexm G PIT.

Application filed April 16,

My invention relates to improvements in the construction and method of operat on of soaking pits such as used in the steel industry for heating ingots prior to rolling.

Heretofore, it has been practically universal practice to provide soaking pits with checker work or regenerative chambers for preheating the air used to support combustion in the soaking pit and it as sometimes been the practice to also preheat the gas used as fuel. The prior practice has been to periodically reverse the direction of travel of the fuel and waste gases. Therefore, the prior types of soaking pits required usually' two sets of regenerative or so-called checker chambers and various forms of reversing valves and conduits for reversing the direction of travel of the fuel and waste gases to and from the soaking pit. My invention eliminates the necessity of installing regenerative chambers such as previously used and does away with reversing valves and other necessary operating gear. The economies effected b my construction, conservatively estimate amounts to about one-third of the cost of prior constructions. M invention will be apparent from the 0 lowing specification when read in connection with the accompanying drawings and the features of novelty will be pointed out with particularity in the appended claims. In the drawings Fig. 1 is a plan view of a four hole soaking pit with certain parts shown in horizontal section;

Fig. 2 is a longitudinal section on line 2-2 of Fig. 1;

Fig. 3 is an enlarged horizontal section on line 3-3 of Fig. 2;

Fi 4 is an enlarged plan of parts shown in Figs. 1 and 2;

Fig. 5 is a section on line 5-5 of Fig. 4 of certain parts in front of the plane in section shown in elevation.

Referring in detail to' the drawings, the soaking pit includes side walls 10 and 12, end walls 14 and 16 and several division walls 18 which in the embodiment shown divide the structure into a four hole soaking pit, each hole or pit being indicated in the drawing by numeral 20. The several pits are substantially duplicates therefore a description of one will suflice for all. Each pit is open at the top and a removable cover or roof 22 is supported by a carriage 24 ar- 1926. Serial No. 102,443.

ranged to travel along tracks 26 carried by a suitable super-structure 28. Extending longitudinally below the row of pits 20 is a scale tunnel 30. At one side of this tunnel there is located for each pit 20 a recuperator indicated as a whole by numeral 32. Each recuperator is in communication with a suitable flue 34 leading to a stack 36 to which the waste gases from the several soaking pits are discharged.

Extending longitudinally at each side of the soakin pit are gas headers 38 and 40 for supplying fuel to the burners 42 and 44, respectively. Parallelling the gas headers 38 and 40 are air headers 46 and 48. These air headers are connected with one another by cross pipes 50 and the air supplied them is preheated by the waste gas flowing through the recuperators 32. Each recuperator is provided at the top with a hood 52 which connects by pipe 54 with a fan 56 which in turn is connected at 58 with the air header 48.

Fresh air enters the recuperators through vertical flues 60 having suitable dampers 62 and 64 therein controlling the passage of air to the horizontal passages 66 and 68, respectively. The fresh air from the horizontal passages 66 and 68 flows upwardly as indicated by arrows y through the air chambers 69 of the recuperators to the hood 52 where it is forced by the fan to the burners where it mixes with the fuel and enters the furnace as a combustible mixture under pressure as will be understood. The burners 42 and 44 it is noted are direct gas-fired burners in which air and as mixes in the inspirators 70 and 72 outsi e of the soaking pits. The flame in the soaking pits is propagated in the flame chambers 73 on the opposite ends thereof. These opposed burners are operated simultaneously so that the ingots indicated in dotted lines at 74 are quickly and uniformly brought to the proper temperature. The waste gases from the soaking pit flow by the way of the centrally locatedports 76 to the fiues 78 which communicate with the ports 79 leading to chambers 80 of the recu erator. The hot waste gases flow in the direction of the arrows w in a circuitous manner through chambers 80, 82 and 84 to the flue 34 which leads to the stack. The flow of the waste gases is in a unidirectional path. That is to say. they are not reversed as is the case in soaking-pits heretofore used. In some cases, I pro ose to control the temperature of air supp ied to the headers 46 and 48. For this purpose I provide a thermo-couple indicated diagrammatically at 86 which is connected to a suitable device 88 adapted through the link mechanism 90 to move a butterfly valve 92 for controlling the admission of cold air through a branch pipe 94 connected with the pipe 54 which leads to the inlet side of the In operation, the ingots to be treated are lowered into the pit 20 by any suitable form of overhead tackle and the roof or cover 22 is moved to the position shown in Fig. 2. The ingots are then subjected to the heat from the oppositely disposed burners 42 and 44 which simultaneously direct the non-oxidizing or neutral fiame toward the ingots. The waste gases continuall pass in the same unidirectional path throug the recuperators in their journey to the stack. At the same time fresh air is continuously passing in heat exchanging relationship through the recuerator to the air headers connected to the Burners. The recuperators are of such design that there will be very little pressure within the passages thereof. This tends to eliminate the tendency of the waste gases leaking into the fresh air passages. My dedoes away with the use of usual forms 0 regenerators or checker chambers and eliminates the usual reversing valves and operating mechanism. My improved design reduces the gas consumption from about 4000 cubic feet per ton of ingots to about 2000 cubic feet of gas per ton. The first cost of installation of my pit is much less than the cost of prior types and the maintenance cost will be reduced at least one-half. In practice I have found that my construction reduces the cinder and scale loss from about 2 down to about 1%. This saving in oxidation of ingots will practically pay for the cost of fuel required to heat the steel. My invention makes it possible to continuously maintain a reducing atmosphere in the soaking pit. This saves losses in the oxidation of the material heated.

The ingots treated in my soaking pit cannot be overheated or burned due to negligence of the heater or operator in charge of the pit. The amount of air supplied to sup port combustion is automatically varied in accordance with the amount of fuel supplied. In this way, I am able to maintain a non-oxidizing or reducing atmosphere in the pit.

The invention herein described has been reduced to actual practice in a commercially operable installation and the savings both in operation and construction costs referred to are based on actual performances. The invention therefore marks a decided advance in the art.

Though I have described quite specifically the embodiment of the invention herein il lustrated, it is not to be construed that I am limited thereto since various changes may be made by those skilled in the art without departure from the invention as defined in the appended claims.

What I claim is 1. A soaking pit furnace having a removable top to permit insertion and removal of the ingots in combination with a recuperator. a fuel gas main and an air main located outside the furnace and a waste gas outlet. means for drawing fresh air through said recuperator and delivering it to said air main. and means for passing the waste gas from the pit in a uni-directional path through said recuperator to said waste gas outlet to atmosphere.

2. A soaking pit furnace having a burner element connected with a gas supply pipe located outside the pit, a recuperator, a fan arranged to draw air through said recuperator and having a connection through which heated air is supplied to said burner element outside the furnace structure.

In witness whereof, I have hereunto signed my name.

HERBERT C. RYDING. 

